Field of the Invention
The present invention relates to a method for avoiding interference between adjacent basic service sets (BSSs) in a wireless local area network (hereinafter referred to as ‘WLAN’) system and an apparatus for performing the same.
Related Art
In recent years, as supply and use of mobile devices such as a smart phone and a tablet personal computer (PC) have increased, a use zone and a user of a WLAN using a non-licensed band have rapidly increased. In at least half of internet traffic previously depends on the WLAN. Accordingly, interference between adjacent access points (APs) and interference between stations (STAs) associated with adjacent different APs, that is, included in different BSSs become a main cause to lower performance of the WLAN. In order to efficiently use a frequency resource, to solve interference between adjacent BSSs is extremely attractive. In order to minimize the interference between BSSs and to efficiently use the frequency resource, a distribution state of an AP and an STA causing interference between BSSs is recognized. Accordingly, it is important to apply an effective interference avoiding method.
As an example of a method for avoiding interference in a WLAN, Korean Patent Publication No. 10-2003-0018051 (published on Mar. 4, 2003) discloses an overlapping network allocation vector for avoiding collision in IEEE 802.00 WLAN operating under an HCF. In Korean Patent Publication No. 10-2003-0018051, a method for avoiding collisions between a plurality of stations located in two or more basic service sets (BSSs) and operating in the same channel, includes the steps of: the mobile station receiving a frame, the frame including information indicative of which of basic service sets (BSSs) are transmitting the frame to the mobile station; the mobile station updating a first counter when the received frame is determined to be from its corresponding BSS; the mobile station updating a second counter when the received frame is determined to be from an overlapping BSS; and, the mobile station transmitting within its corresponding BSS when the first counter and the second counter are zeros. Meanwhile, for example, an existing method of avoiding interference between BSSs includes a centralized interference avoiding method using an AP controller applied to an enterprise network and a method of avoiding interference based on energy detection based on clear channel assessment (CCA). The centralized interference avoiding method is available in a business network or an enterprise network but has a difficulty in being used between other business networks, in public places, and an environment in which private APs exist. The method of avoiding interference based on energy detection based on clear channel assessment (CCA) has a difficulty in efficiently avoiding interference according to various distribution situations of the AP and the STA causing interference between BSSs. Accordingly, there is a need for a method of avoiding interference in a new scheme capable of being widely and generally used to be applicable to a WLAN standard technology by taking into consideration an interference situation between BSSs having various forms, and an information exchange method using the same.